What is the Best and Safest Way to Connect Lithium Batteries in Parallel for RVs and Boats or Homes?

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I wrote an article about this a year ago and I am finally getting around to making it into a YouTube video. The written version is short but it has more details. Please give me feedback if you have it. Wiring batteries in my Method A is not a disaster but, the more batteries you have in parallel, the harder the batteries will work and the shorter their life will be.

This video was made from article # 7

Here is my current list of informative RV articles on my website.
List of Articles
1. Choosing How to Power Your RV An Analysis of What You Really Need
2. What is an Amp Hour Ah and How Does it Apply to Your RV?
3. What is a Watt Hour Wh and how it applies Amp Hours and to your RV? Also a short summary of RV batteries
4. Why You Need a Shunt Battery Monitor in Your RV
5. Evaluating How Long Your RV Battery Will Last Off Grid
6. Stock Solar with 12V RV Refrigerator Not Charging Battery
7. The Best Way to Connect Batteries In Parallel
8. Interactive Tool to Evaluate How Long Your Battery Will Last During Certain Weather, Battery Sizes, Loads and Panel Wattages
9. A Simple Way to Add Extra Solar Panels to the Existing Furrion Solar Controller
10. Using Water Columns to Represent Charging a Battery
11. How Does a 50 Amp RV Service Compare to a 30 Amp RV Service?

I also have a growing list of Ukulele articles and Videos.
"See 10 Reasons Why You Need a Traveling Ukulele in Your RV" As well as other related stuff!!!

[prepparig]

Great video, very helpful. Also viewed that video link you put in one of your responses of the person testing the 3 setups. It's all black and white now. Thank you!!

[zyxyruf]

use a bus bar with two or more batters.

[leapnlarry]

This is one of the first things i learned when i designed my solar system 4 years ago, very true. I should make a short about it. Larry

[offgridwanabe]

What about Method C, all cables the same length go to a bus bar then a large cable goes to the charge / discharge apparatus.

[brycemcleod]

Can the two lithium batteries be separated by distance... One under the bonnet of a car and the second in the boot of the car? I currently have a itech lithium battery under the bonnet that i run my camping fridge off and want to add a second to double the capacity

[djperfecto]

Dear friend thanks for your video...what is the proper connection of the power inverter?direct positive and negative one battery 1 or 2? Or positive on battery 1 and negative one battery 2?
Thanks!!!

[geoffculp]

Seems like there could be a diod on the discharge if 1dosent charge or disharge as much it wont be drawing away from others of more capacity n maybe have sepret wires between each for balance charging and monitoring each and not having to unhook them not shure what size diod can carry what ampraje though ones in a car alternator seem big to me guess there called a bridge rectifer in an alternater to though.

[zykhrpm]

My electric scooter has a 48v 30ah LFP battery. And I want to add another 48v 18ah battery to it. Can I connect both positive and negative in parallel at the charging point?

[notconnected]

I think that the point here is, that all batteries should have the same overall cable length (positive and negative added together). Because i guess modern batteries have such a low internal resistance, that it forms a voltage divider with the (also very low) resistance of the cable.
The effect could alternatively be minimized by using thicker cables, that have significantly lower resistance compared to the battery's internal resistance.

[Bilskirnir]

Can you define/elaborate on “a period of time”. Days, weeks years? Running time/idle time etc. thanks in advance

[rithlim]

Great video! I could be wrong but I think in "Method B more extreme example", if you connect the positive load cable to Battery 3 (versus Battery 4) and connect the negative load cable to Battery 2 (versus Battery 1), you'd get a more even distribution of power while charging and under load. This will better help the lifespan of all the batteries.

[princesunnyboy]

How to connect with 3 batteries or more?

[falcorthewonderdog]

No mention of any lithium battery monitoring device. You can't just hook lithium batteries to a system designed for lead acid you need a charging controller to isolate the lithium battery for the lead acid battery.

[TheCSRTech]

In what way is hook-up B SAFER than hookup A?

[davidbuchanan]

Good info for me as Im currently designing my system in my Lance truck camper. Space is limited and the camper came with only one battery. I have removed the microwave and added 2 lithium batterys, solar charge controller and some fuses and buss bars in that space. From the buss bars in that space I will connect to the camper battery. So I will have 3 100ah batterys and 400 watts of solar and a 2000 watt inverter. The camper also has a propane generator which connects to a transfer switch. I hope it all works when Im done.

[Jarda_B]

The resistance of the cable it not as big as you think, if you are not cheepo.

if you use 16mm2 cable to cenect them and have proper conection it will not go over 1 ohm in total.
1m of cable like this have 0, 00013ohms, if it will not go over 0, 5 ohm there is not going to be a noticible difference.

[Ed]

I have a very hard time to believe this. Any regular wire will have a negligentv esistance. Are you using meters of resistance wire to connect your batteries.?

[sleddy]

I love videos that open with music i hate

[EarlBalentine]

Mine batteries look like the Method B.

[brianrhodebeck]

You didn't mention, Lithium batteries. Having B u s s bars with charging on each Battery is equally Charged